Internal crankshaft millers, or millers of internal type for fabricating crankshafts make use of an inside edge cutter having a plurality of tips or cutting edges attached thereto along its inner peripheral surface, and cutter changing systems or apparatuses for use with such millers have been known as disclosed, e. g., in patent literature JA P 8-118125 A and JA U 6-5816 A.
JA P 8-118125 A describes a cutter mounting apparatus having a construction in which two or more splines are arranged circumferentially spaced apart and equi-distantly along the outer periphery of a pin forming miller cutter corresponding to the splines, spline slots are formed along the inner periphery of an adapter. The splines and the spline slots to be fitted together are tapered to become gradually narrower in the forward direction in which the cutter is inserted into the adapter. Such a construction is described to prevent a thermal expansion from making the fit tight and a tilt of the cutter pulled out from causing the fit to misfit, and thus to have the advantage of permitting the pin forming miller cutter to be centered with precision and yet to be mounted and dismounted with ease.
JA U 6-5816 A describes a cutter mounting apparatus in which a cutter body has a key slot formed therein that is tapered with respect to a longitudinal axis of the cutter body to accept and fit with a cutter adapter key. It is taught that the arrangement permitting the cutter body if thermally expanded to be readily removed from the cutter adapter is thus capable of effecting a cutter changing operation in a short period of time and with ease.
Inconveniently, however, both the cutter mounting apparatuses described above require that a cutter body upon being mounted on the cutter adapter be fixed to the cutter adapter with a plurality of clamping bolts fastened to both the cutter body and the cutter adapter.
In removing the cutter body from the cutter adapter, this also requires that these clamping bolts be loosened and detached to release the cutter body from the cutter adapter.
The prior art is found inconvenient in that it entails a time consuming operation in loading and unloading a cutter body and is hence inefficient. Further, the cutter mounting method with a plurality of clamping both described above is a big factor in holding back an automatization of the cutter changing.